Re: [PATCHv3 1/3] USB: gadget: mass/file storage: set serial number

Alan Stern
2010-07-20T15:02:29Z

On Tue, 20 Jul 2010, [utf-8] MichaÅ‚ Nazarewicz wrote:

> I wanted to keep fsg_string_serial_fill() as a macro so that it can
> use ARRAY_SIZE() on the first argument to check the size. If there
> was a single function it would have to explicitly take the length of
> the destination array as an argument -- that's what the *_n() function
> is for.
>
> The rationale is that not having to use ARRAY_SIZE() is, well,
> simpler. ;)

My advice is don't bother. Let callers give explicitly the size of
their buffer. How many other routines in the kernel do an implicit
ARRAY_SIZE on behalf of their callers? What if the buffer is passed as
a pointer instead of as an array?

> Basically, what you are proposing is to remove the
> fsg_string_serial_fill() macro and leave only the *_n() changed to
> an inline function and force all callers use sizeof/ARRAY_SIZE().

Or determine the size in some other way. Yes. (And then remove the
"_n" from the name since it will be unnecessary.)

> Am I getting that right? Personally, I'd leave things like they are
> changing the *_n() to a function. What do you think?

See above.

Alan Stern